Researchers at the Nano Life Science Institute (WPI-NanoLSI) at Kanazawa University in Japan have developed a new biosensor for improved detection of 1-methylnicotinamide (1-MNA) metabolites in urine.
The biosensor achieves this with an increase in sensitivity while eliminating the need for sample purification.
Metabolites are key biomarkers for various diseases, including cancer, liver disease, obesity, and metabolic disorders.
The researchers used a specialised type of pillararene molecule as a biosensor to replace methods like mass spectrometry and nuclear magnetic resonance. These traditional techniques are often costly and complex, limiting their accessibility.
This approach bypasses the requirement for high purification of 1-MNA biosensing molecules, while simultaneously enhancing both sensitivity and specificity.
In their report, the researchers highlighted that monitoring nicotinamide N-methyltransferase (NNMT) expression and activity in patients through 1-MNA quantification is important for understanding and diagnosing their conditions.
Previously, they demonstrated the potential of using a pillar[6]arene molecule functionalised with 12 carboxylate anions (P6AC) as a 1-MNA sensor.
To improve sensitivity, the researchers explored the use of pillar[6]arene functionalised with sulphonate groups (P6AS). They found that P6AS has a binding affinity 700-fold greater than P6AC, resulting in a biosensor capable of sub-micromolar sensitivity even in unpurified human urine.
The researchers found that while the detection of larger quantities in murine urine was more successful, high autofluorescence levels made it more difficult to detect higher concentrations in human serum.
Additionally, the team proposes that the high throughput of the P6AS biosensor could facilitate the screening of thousands of potential NNMT inhibitors. This will advance treatments for diseases such as liver disease and cancer.
Furthermore, the increased sensitivity of the P6AS biosensor is attributed to the stronger acidity of sulphonate groups compared to carboxylate groups.
In conclusion, WPI-NanoLSI’s researchers said: “Further improvement of our strategy will contribute to high-throughput screening of NNMT inhibitors, diagnosis of liver diseases, and imaging of human cancer cells in vivo.”
In July, the researchers reported in Small Methods the 3D imaging of a suspended nanostructure. The technique is an extension of atomic force microscopy (AFM) to visualise 3D biological systems.
